Tweak statScore condition

The first change (ss->statScore >= 0) does nothing.

The second change ((ss-1)->statScore >= 0 ) has a massive change.
(ss-1)->statScore is not set until (ss-1) begins to apply LMR to moves.
So we now increase the reduction for bad quiets when our opponent is
running through the first captures and the hash move.

STC
LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 57762 W: 10533 L: 10181 D: 37048

LTC
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 19973 W: 2662 L: 2480 D: 14831

Bench: 5037819